JP3567718B2 - Inner lead bonding method and apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inner lead bonding method and apparatus, and more particularly to an inner lead bonding method and apparatus capable of improving the joining accuracy between an IC chip and an inner lead, reducing the number of cleanings and improving the joining efficiency.
[0002]
[Prior art]
In a process of TAB (Tape Automated Bonding) technology, an inner lead bonding device (hereinafter, referred to as a bonding device) is used to bond an IC chip to inner leads protruding from device holes provided in a film carrier. This is an upper and lower clamp capable of fixing a device hole continuously formed in a long film carrier, a bonding stage provided below the clamp and capable of holding an IC chip, and a bonding stage provided above the clamp and provided above the clamp. And a bonding tool capable of pressing the IC chip. The position of the three members is adjusted, and the bonding tool is lowered so that the electrodes of the IC chip are bonded to the inner leads.
[0003]
By the way, in order to lower the bonding tool and connect the inner lead to the electrode of the IC chip, heating and pressurizing are required. Specifically, the temperature on the bonding tool side is set at about 500 ° C., and the temperature on the bonding stage side is set in the range of 90 to 300 ° C. The joining load is set in the range of 3 to 20 kgf, and the pressing is performed under this condition for about 500 ms.
[0004]
[Problems to be solved by the invention]
However, when the inner leads are made finer and the thickness of the film carrier (polyimide) becomes thinner along with this, deformation occurs around the device holes due to radiant heat from the surroundings, and the bonding accuracy between the inner leads and the IC chip is reduced. There was a risk of getting worse.
[0005]
Also, the thickness of the inner lead (the thickness of the copper foil) becomes thinner as the film carrier becomes thinner, so the inner lead itself is crushed by heating and pressing from the bonding tool, and the inner lead itself is damaged, In addition, there is a risk of contact with an adjacent inner lead.
[0006]
Furthermore, in the case of tin-plated inner leads, the tin oxide may adhere to the bonding tool during bonding and the bonding strength may be reduced. Therefore, the tip of the bonding tool must be cleaned at regular intervals. Since this cleaning process requires several seconds to several tens of seconds (the bonding time is about 500 ms), the efficiency of the bonding operation is greatly reduced. In addition to the tin, the adhesive used for the film carrier at the time of bonding is vaporized by radiant heat and adheres to a bonding tool, a clamp, a bonding stage, etc., which causes a reduction in bonding strength and a variation in accuracy of IC chip supply. For this reason, it was necessary to periodically clean the bonding apparatus itself.
[0007]
The bonding tool is used at a high temperature of about 500 ° C., and thus has a problem that its life is short.
[0008]
The present invention pays attention to the above-mentioned conventional problems, and provides an inner lead bonding method and apparatus capable of performing bonding between an inner lead and an IC chip even at a relatively low temperature and reducing adverse effects due to radiant heat. Aim.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an inner lead bonding method according to claim 1 of the present invention is an inner lead bonding method for solid bonding an inner lead on a tape to an electrode provided on an IC chip,
Halogenating at least one surface of the inner lead and the electrode,
By the inner lead bonding device after the halogenation treatment ,
It is characterized in that the inner lead and the electrode are joined to each other via a halogenated surface to form a solid joint.
[0010]
An inner lead bonding apparatus for solid bonding having a component mounting section having a long tape transport path and an IC chip transport path according to claim 2 of the present invention,
A halogenation processing unit is provided in at least one of the long tape transport path and the IC chip transport path,
A buffer section of a film carrier is provided between the IC chip transport path and the halogen processing section, and a processing timing of the halogen processing section and the bonding processing section is adjusted,
Halogenating at least one of the surface of the inner lead provided on the long tape and the surface of the electrode provided on the IC chip;
The component mounting portion may join the conductor electrode portion and the component connection land to each other via a halogenated surface to form a solid joint.
[0011]
When these inner lead bonding methods and inner lead bonding apparatuses are used, since solid bonding can be performed, the heating and pressing conditions can be reduced, and the influence of radiant heat or the like on the bonding target can be reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of an inner lead bonding method and apparatus according to the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a process explanatory view of mounting an IC chip on a film carrier using the inner lead bonding apparatus according to the present embodiment.
[0014]
As shown in FIG. 1, an inner lead bonding apparatus 10 (hereinafter, referred to as a bonding apparatus 10) includes a bonding unit 14 for mounting an IC chip 11 on a film carrier 12 and a preceding stage of the bonding unit 14; And a fluorination processing unit 16 for fluorinating the surface.
[0015]
A delivery roll 18 around which the film carrier 12 is wound and a driven sprocket 20 are provided on the upstream side of the bonding apparatus 10 in the mounting process, while a take-up roll 22 for taking in the film carrier 12 and a drive are provided on the downstream side of the bonding apparatus 10. A sprocket 24 is provided. Here, the driving sprocket 24 can bite into sprocket holes 26 (see FIG. 2) provided in both widths of the film carrier 12, and the movement of the film carrier 12 in conjunction with the operation of the bonding unit 14 described later. Stopping is possible.
[0016]
FIG. 2 shows a front view of the film carrier 12. As shown in the figure, the film carrier 12 is in the form of a long tape made of polyimide, and a plurality of sprocket holes 26 are arranged at both widths along the longitudinal direction. A rectangular device hole 28 for accommodating the IC chip 11 is provided at the center of the film carrier 12, and an inner lead 30 protrudes from each edge. An outer lead hole 32 is provided outside the device hole 28, and an outer lead 34 is provided so as to straddle the outer lead hole 32 and is connected to a test pad 36.
[0017]
FIG. 3 is an explanatory diagram showing the configuration of the bonding unit 14. As shown in the figure, the bonding unit 14 includes a bonding stage 38 holding an IC chip 11 to be bonded and having a heater 42, a heater 42, an IC chip recognition camera 41 and a film recognition camera 43, and a bonding stage 38. A bonding tool 40 provided above the IC chip 11 for heating and pressurizing the electrode 11A of the IC chip 11 to join the inner lead 30 and a film carrier 12 sandwiched from above and below during the bonding operation to fix the position. And upper and lower clamps. The bonding stage 38 can be lowered by a cylinder (not shown), and the bonding stage 38 moved to the lowest point is provided with an IC chip recognition camera above it. Can be supplied. Note that an IC recognition camera 48 is provided above the tray 46. If the image from the IC recognition camera 48 determines that the tray 46 is empty, a new tray 46 is pulled out from the magazine loader 50, and the IC chip 11 continuous supply is possible.
[0018]
FIG. 4 is an explanatory diagram illustrating a configuration of the fluorination processing unit 16.
[0019]
As shown in the figure, the fluorination treatment section 16 is composed of a reaction chamber 52, an HF gas supply section 54, and a steam generation section 56, and a mixed gas of HF gas and steam is supplied through pipes 58 and 60. It is supplied to the reaction chamber 52. When the film carrier 12 comes into contact with the mixed gas, the inner leads 30 projecting from the device holes 30 are fluorinated.
[0020]
That is, when the inner lead 30 is exposed to a mixed gas of HF gas and water vapor, HF and H ₂ O are formed on the surface of the inner lead 30.
[0021]
Embedded image
_{HF + H 2 O → (H} 3 O) + + F -
Occurs, and the fluorine ions (F ⁻ ) react with the inner lead 30 to fluorinate the surface of the inner lead 30. By the way, since the inner lead 30 is made of metal, its surface is covered with a natural oxide film, and the surface of the oxide film is fluorinated by a substitution reaction between oxygen and F-, or a mixture of fluorine and oxygen is formed. A surface having the composition is formed.
[0022]
When the inner lead 30 is fluorinated, it is necessary to stop the transfer of the film carrier 12 independently of the cycle time of the bonding unit 14. For this reason, a buffer 62 is provided between the fluorinated portion 16 and the bonding unit 14 for storing a predetermined amount of the fluorinated film carrier 12 in advance (adjusting the buffer amount with the L dimension). It is possible to continuously supply the film carrier 12 to the bonding unit 14 even when the transport of the film carrier 12 is stopped on the fluorination processing unit 16 side. It is to be noted that the reaction chamber 52 has a capacity enough to receive the plurality of device holes 28 so that the capacity of the buffer unit 62 at the subsequent stage is not lost. The fixing of the film carrier 12 in the fluorinated portion 16 is performed by positioning pins 64 that can be inserted into and removed from the sprocket holes 26.
[0023]
By the way, the above-mentioned fluoridation section 16 is provided in the next stage of the delivery roll 18, but before the delivery roll 18, that is, the fluorination section 16 is made independent and the inner lead 30 side is subjected to fluorination treatment in advance. You may make it.
[0024]
A procedure for mounting the IC chip 11 on the inner lead 30 using the bonding apparatus 10 configured as described above will be described.
[0025]
First, the film carrier 12 is unwound from the delivery roll 18 and wound around the take-up roll 22. Then, the film carrier 12 is taken into the reaction chamber 52 to form the buffer section 62, and the film carrier 12 is fixed by the positioning pins 64. After taking in the film carrier 12 in the reaction chamber 52, the mixed gas is sent from the HF gas supply unit 54 and the vapor generation unit 56 to the reaction chamber 52 via the pipes 58 and 60, and the inner leads 30 projecting from the device holes 28. Perform fluoridation treatment.
[0026]
When the fluorination of the inner lead 30 is completed, the positioning pin 64 is pulled out from the sprocket hole 26, the film carrier 12 is drawn out of the reaction chamber 52, and the buffer section 62 is formed.
[0027]
After the buffer section 62 is formed, the bonding unit 14 and the fluorination processing section 16 are operated to simultaneously perform the fluorination processing of the inner leads 30 and the connection of the IC chip 11.
[0028]
When the driving sprocket 24 is rotated, the fluorinated film carrier 12 moves to the bonding unit 14 side. When the device hole 28 moves to a predetermined position, the driving sprocket 24 stops, and the upper and lower clamps (not shown) sandwich the film carrier 12. This state is confirmed by the film recognition camera 43 installed on the side of the bonding tool 40. The film carrier 12 is sandwiched between the clamps, and the position of the electrode 11A of the IC chip 11 mounted on the bonding stage 38 is captured by an IC camera 41 provided above the bonding stage 38. Then, the bonding stage 38 on which the IC chip 11 is mounted moves to a position substantially at the center of the device hole 28 and rises. The position of the inner lead 30 and the bonding tool 40 is corrected from the image captured by the film recognition camera 43, and the position of the inner lead 30 and the electrode 11A of the IC chip 11 is corrected from the image captured by the IC chip camera 41. When the position correction of both is completed, the positioning of the electrode 11A, the inner lead 30, and the front end of the bonding tool 40 is completed.
[0029]
After the positioning of the electrode 11A of the IC chip 11, the inner lead 30, and the tip of the bonding tool 40 is completed, the bonding tool 40 is lowered, the inner lead 30 is pressed against the electrode 11A, and the two are joined. By the way, the surface of the inner lead 30 is fluorinated in a stage before being put into the bonding unit 14, that is, in the reaction chamber 52. Therefore, when the inner lead 30 is brought into contact with the electrode 11A, the two can be joined even under a relatively low temperature and a low pressure (joining load).
[0030]
The mechanism of this joining is considered as follows. The atoms of the surface of the inner lead 30 that are bonded to fluorine are broken by contact with the electrode 11A and are bonded to the atoms of the electrode 11A, thereby joining the two. Then, it is considered that the broken fluorine is diffused into the inside of the bonding member that easily takes in the fluorine.
[0031]
As described above, when the solid bonding between the inner lead 30 and the electrode 11A is performed at a relatively low temperature (the conventional bonding tool 40 is set at about 500 ° C.) and low pressure (the bonding load of the conventional bonding tool 40 is about 3 to 20 kgf). Therefore, the film carrier 12 is less likely to be affected by radiant heat from the bonding tool 40 and the bonding stage 38. Therefore, the deformation of the film carrier 12 is suppressed, so that the forming is stabilized, and the bonding accuracy with the IC chip 11 can be improved. In addition, since the heating temperature can be set low, the generation of a heat haze around the recognition camera can be suppressed. For this reason, it is possible to improve the positioning accuracy of the IC chip 11, the inner lead 30, and the bonding tool 40. On the other hand, since the joining can be performed with a low load, the inner leads 30 can be prevented from being damaged or crushed and from contacting with the adjacent inner leads 30. Further, generation of gas (mainly due to the adhesive) from the film carrier 12 due to radiant heat from the tools is suppressed, or tin oxide is less likely to adhere to the bonding tool, so that cleaning of the tools is performed. The interval can be widened. For this reason, it becomes possible to improve the operation rate of the present apparatus 10.
[0032]
Conventional alloy formation is considered to be affected by the bonding strength depending on the surface condition of the object to be bonded and the plating thickness of the surface, but the solid bonding shown in the present invention is based on the movement between atoms (chain, diffusion). Therefore, there is a possibility that the joining margin is widened.
[0033]
In the case of fine pitch, the strength of the lead itself (copper foil) is more important than the strength of the joint, but the solid bonding at low temperature does not damage or deform the lead due to heat, so the actual bonding strength may be improved. There is.
[0034]
Then, the film carrier 12 on which the IC chip 11 is mounted moves from the bonding unit 14 to the subsequent stage, is stored in the take-up roll 22, and is taken over to the next step.
[0035]
By the way, in the present embodiment, the fluoridation treatment of the inner lead 30 is performed. However, the present invention is not limited to this embodiment, and the IC chip 11 may be fluorinated instead of the inner lead 30. Both may be fluorinated and joined.
[0036]
FIG. 5 is an explanatory diagram for fluorinating the IC chip 11 side.
[0037]
As shown in FIG. 1A, a reaction chamber (not shown) is formed so as to surround the tray 46, and a mixed gas of HF gas and water vapor is introduced into the reaction chamber to fluorinate the surface of the IC chip 11. It may be. Further, as shown in FIG. 2B, a mask 68 may be attached to the wafer 66 before dicing, and only the electrode 11A may be fluorinated.
[0038]
Further, in the embodiment, the case where the halogen is fluorine has been described. However, the halogen may be chlorine, iodine, bromine, or the like depending on the compatibility or the surface state of the bonding partner.
[0039]
【The invention's effect】
As described above, according to the present invention, there is provided an inner lead bonding method for bonding an inner lead projecting from an edge of a device hole to an electrode provided on an IC chip, wherein at least one surface of the inner lead and the electrode is halogenated. And the inner lead and electrode are joined to each other via a halogenated surface to form a solid joint.This reduces the effects of radiant heat from tools, improves joining accuracy, and widens the cleaning interval of the equipment. can do. For this reason, the operation rate (productivity) can be improved.
[Brief description of the drawings]
FIG. 1 is a process explanatory view of mounting an IC chip on a film carrier using the inner lead bonding apparatus according to the present embodiment.
FIG. 2 shows a front view of the film carrier 12. FIG.
FIG. 3 is an explanatory diagram showing a configuration of a bonding unit 14.
FIG. 4 is an explanatory diagram illustrating a configuration of a fluorination processing unit 16;
FIG. 5 is an explanatory diagram for fluorinating the IC chip 11 side.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Inner lead bonding apparatus 11 IC chip 12 Film carrier 14 Bonding unit 16 Fluorination processing part 18 Delivery roll 20 Follower sprocket 22 Take-up roll 24 Drive sprocket 26 Sprocket hole 28 Device hole 30 Inner lead 32 Outer lead hole 34 Outer lead 36 Test Pad 38 Bonding stage 40 Bonding tool 41 IC chip recognition camera 42 Heater 43 Film recognition camera 44 IC transport 46 Tray 48 IC recognition camera 50 Magazine loader 52 Reaction chamber 54 HF gas supply unit 56 Steam generation unit 58 Pipe 60 Pipe 62 Buffer section 64 Positioning pin 66 Wafer

Claims (2)

An inner lead bonding method for solid bonding an inner lead on a tape to an electrode provided on an IC chip,
Halogenating at least one surface of the inner lead and the electrode,
By the inner lead bonding device after the halogenation treatment ,
An inner lead bonding method, wherein the inner lead and the electrode are bonded to each other via a halogenated surface to form a solid bond. An inner lead bonding apparatus for solid bonding having a component mounting portion having a long tape transport path and an IC chip transport path,
A halogenation processing unit is provided in at least one of the long tape transport path and the IC chip transport path,
A buffer section of a film carrier is provided between the IC chip transport path and the halogen processing section, and a processing timing of the halogen processing section and the bonding processing section is adjusted,
Halogenating at least one of the surface of the inner lead provided on the long tape and the surface of the electrode provided on the IC chip;
An inner lead bonding apparatus, wherein the conductor mounting portion and the component connection land are joined to each other via a halogenated surface at the component mounting portion to form a solid joint.

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